Recently, much development is being conducted of organic light-emitting devices having light-emitting layers containing organic light-emitting materials, examples of which include organic electroluminescence (EL) panels and organic EL lighting devices.
When forming a light-emitting layer through a wet process, an ink (solution) containing an organic light-emitting material and a solvent is used. In connection with this, it is known that ink undergoes degradation when exposed to light. In view of this, Patent Literature 1 discloses a method of forming organic layers including a light-emitting layer by performing a wet process in an environment where light components with wavelengths shorter than the maximum absorption wavelength of the light-emitting material is blocked (e.g., light components with wavelengths of 500 nm or shorter are blocked).